CN104853842A - Shell catalyst for the oxidative dehydrogenation of n-butenes into butadiene - Google Patents

Abstract

The invention relates to a shell catalyst, comprising (a) a carrier body, (b) a shell containing a catalytically active multi-metal oxide containing molybdenum and at least one additional metal, wherein the shell is constructed of multi-metal oxide particles having a d50 value of 6 to 13 [mu]m, which shell catalyst can be obtained by (i) producing a multi-metal oxide precursor mass containing molybdenum and at least one additional metal, (ii) producing a molded body from the multi-metal oxide precursor mass, (iii) calcination of the molded body made of the multi-metal oxide precursor mass in order to produce a multi-metal oxide mass, (iv) grinding the molded body made of multi-metal oxide mass in order to form multi-metal oxide particles having a d50 value of 6 to 13 [mu]m, (v) coating the carrier body with the multi-metal oxide particles, (vi) thermally treating the coated carrier body.

Description

For n-butene oxidative dehydrogenation being become the core/shell-type catalyst of butadiene

The present invention relates to the coated catalysts for n-butene oxidative dehydrogenation being become butadiene, n-butene oxidative dehydrogenation is become purposes and the method for butadiene by it.

Butadiene is a kind of important basic chemical and for such as preparing synthetic rubber (dienite, SBR styrene butadiene rubbers or acrylonitrile-butadiene rubber) or for the preparation of thermoplasticity terpolymer (acrylonitrile-butadiene-styrene copolymer).Butadiene also changes into sulfolane, chlorobutadiene and Isosorbide-5-Nitrae-hexamethylene diamine (by Isosorbide-5-Nitrae-dichloro-butenes and adiponitrile).In addition, butadiene can dimerization with produce can dehydrogenation to form cinnamic VCH.

Butadiene is by the preparation of thermal cracking (steam cracking) saturated hydrocarbons, and wherein naphtha is typically used as raw material.The steam cracking of naphtha obtains methane, ethane, ethene, acetylene, propane, propylene, propine, allene, butane, butylene, butadiene, butine, methyl-prop diene, C ₅the hydrocarbon mixture of hydrocarbon and more higher hydrocarbon.

Butadiene also obtains by the oxidative dehydrogenation of n-butene (1-butylene and/or 2-butylene).Any mixture comprising n-butene can be used as starting gas mixture n-butene oxidative dehydrogenation being become butadiene.Such as, can use and comprise the cut of n-butene (1-butylene and/or 2-butylene) as key component, this cut passes through by the C from naphtha cracker ₄cut is by removing butadiene and isobutene obtains.In addition, comprise 1-butylene, cis-2-butene, Trans-2-butene or its mixture and also can be used as starting gas by the admixture of gas that the dimerization of ethene obtains.In addition, the admixture of gas comprising n-butene obtained by fluid catalytic cracking (FCC) can be used as starting gas.

Comprise n-butene and be used as n-butene oxidative dehydrogenation to become the admixture of gas of the starting gas in butadiene also to prepare by comprising the admixture of gas Non-oxidative dehydrogenation of normal butane.

WO2009/124945 discloses the coated catalysts for 1-butylene and/or 2-butylene oxidation-dehydrogenation being become butadiene, and it can be obtained by the catalyst precarsor comprising following component:

(a) carrier,

B () shell, described shell comprises: (i) comprises molybdenum and other metal of at least one and have urging of following general formula

Change active poly-metal deoxide:

Mo ₁₂Bi _aCr _bX ¹ _cFe _dX ² _eX ³ _fO _y

Wherein:

X ¹=Co and/or Ni,

X ²=Si and/or Al,

X ³=Li, Na, K, Cs and/or Rb,

0.2≤a≤1，

0≤b≤2，

2≤c≤10，

0.5≤d≤10，

0≤e≤10，

0≤f≤0.5, and

The number that y=is determined by the chemical valence of the element beyond oxygen and abundance to realize neutral charge,

(ii) at least one pore-forming agent.

WO 2010/137595 discloses the multi-metal-oxide catalyst for olefin oxidation being dehydrogenated to diene, and it comprises at least molybdenum, bismuth and cobalt and have general formula:

Mo _aBi _bCo _cNi _dFe _eX _fY _gZ _hSi _iO _j。

In the formula, X is the element that at least one is selected from magnesium (Mg), calcium (Ca), zinc (Zn), cerium (Ce) and samarium (Sm).Y is the element that at least one is selected from sodium (Na), potassium (K), rubidium (Rb), caesium (Cs) and thallium (Tl).Z is the element that at least one is selected from boron (B), phosphorus (P), arsenic (As) and tungsten (W).A-j is the atomic fraction of each element, wherein a=12, b=0.5-7, c=0-10, d=0-10, (wherein c+d=1-10), e=0.05-3, f=0-2, g=0.04-2, h=0-3 and I=5-48.In an embodiment, Mo is consisted of ₁₂bi ₅co _2.5ni _2.5fe _0.4na _0.35b _0.2k _0.08si ₂₄the catalyst with the pellet form of 5mm diameter and 4mm height for n-butene oxidative dehydrogenation is become butadiene.

Problem low mechanical stability comprising the shell of active compound normally on coated catalysts.Coated catalysts due to catalyst granules to the mechanical stress of coated catalysts between reactor loading period and during the operation of reactor with the form of lost material in small, broken bits loss active compound.Abrasion activity composition in small, broken bits can build up specific place in the reactor.Local at these, therefore there is very high active compound local concentration, therefore reaction heat removes no longer fully and uncontrollable reaction may occur and accelerates.Uncontrollable reaction reduces the selective of butadiene.In addition, due to overheated, the infringement of other parts to reactor or device may be there is.In catalyst bed, the accumulation of abrasion activity composition also can cause in these local sedimental formation of carbonaceous material occurring improving.The formation of carbonaceous material can cause the pressure drop in catalyst bed to improve.The above-mentioned adverse effect of lost material may make interrupt operation of having to, and this has adverse influence to the economy of method.

The object of this invention is to provide the coated catalysts for n-butene oxidative dehydrogenation being become butadiene, it has the mechanical stability of improvement.

This object is realized by coated catalysts, and described coated catalysts comprises:

(a) carrier,

B () comprises the shell of the catalytic activity poly-metal deoxide containing molybdenum and other metal of at least one, its mesochite is by the d with 6-13 μm ₅₀poly-metal deoxide particle make,

And obtain by following steps:

I () preparation comprises the poly-metal deoxide precursor composition of molybdenum and other metal of at least one,

(ii) formed body is prepared by poly-metal deoxide precursor composition,

(iii) the formed body calcining of poly-metal deoxide precursor composition will be comprised to produce multimetal oxide compositions,

(iv) formed body comprising multimetal oxide compositions is pulverized to form the d with 6-13 μm ₅₀poly-metal deoxide particle,

V carrier is used poly-metal deoxide particle coating by (),

(vi) by the support heat-tr eatment of coating.

Find, its shell is by the d with 6-13 μm ₅₀the coated catalysts of the present invention made of poly-metal deoxide particle demonstrate wearing and tearing low especially.

Poly-metal deoxide particle preferably has 8-13 μm, particularly preferably the d of 9-12 μm ₅₀.

D ₅₀the median particle size based on volume is defined as according to ISO 13320.This particle meaning 50 volume % has and is less than d ₅₀diameter and 50 volume % have and be greater than d ₅₀diameter.

Domain size distribution and d therefrom ₅₀determination of laser light scattering is passed through according to ISO 13320.Such as, domain size distribution measures by such as under type: by dispersion chute, fine-powder is introduced the dry disperser of SympatecRODOS (Sympatec GmbH, System-Partikel-Technik, Clausthal-Zellerfeld), in, disperse by compressed air is dry and is blown in measuring cell as free stream there.Here, the domain size distribution of Malvern Mastersizer S laser light scattering spectrometer (Malvern Instruments, Worcestershire, Britain) mensuration based on volume is passed through according to ISO 13320.

The wearing and tearing of coated catalysts of the present invention can measure in drop test.For this reason, by the such as coating of about 50g and the coated catalysts of heat treatment introduced vertical 350cm long-tube reactor from top through 30 second time.Take out molded catalyst bodies and the fragment in small, broken bits from active compound, be separated from each other and weigh.By the quality of the quality of fragment divided by the gross activity composition put on carrier.Generally speaking, the wearing and tearing of coated catalysts of the present invention are <15%, preferred <11%.

Be suitable for the catalyst of oxidative dehydrogenation usually based on containing Mo-Bi-O poly-metal deoxide system, it also comprises iron usually.Generally speaking, catalyst system comprises other catalyst component from periodic table 1-15 race, such as potassium, caesium, magnesium, zirconium, chromium, nickel, cobalt, cadmium, tin, lead, germanium, lanthanum, manganese, tungsten, phosphorus, cerium, aluminium or silicon.

In a preferred embodiment, poly-metal deoxide comprises cobalt and/or nickel.In another preferred embodiment of the present, poly-metal deoxide comprises chromium.In another preferred embodiment of the present, poly-metal deoxide comprises manganese.

Generally speaking, the catalytic activity poly-metal deoxide comprising molybdenum and other metal of at least one has general formula (I):

Mo ₁₂Bi _aFe _bCo _cNi _dCr _eX ¹ _fX ² _gO _x(I)，

Wherein each variable has following implication:

X ¹=W, Sn, Mn, La, Ce, Ge, Ti, Zr, Hf, Nb, P, Si, Sb, Al, Cd and/or Mg;

X ²=Li, Na, K, Cs and/or Rb,

A=0.1-7, preferred 0.3-1.5;

B=0-5, preferred 2-4;

C=0-10, preferred 3-10;

d＝0-10；

E=0-5, preferred 0.1-2;

F=0-24, preferred 0.1-2;

G=0-2, preferred 0.01-1; And

The number that the chemical valence of the element during x=serves as reasons (I) beyond oxygen and abundance determine.

Example containing the poly-metal deoxide of Mo-Bi-Fe-O is the poly-metal deoxide comprising Mo-Bi-Fe-Cr-O or Mo-Bi-Fe-Zr-O.Preferred system is such as described in US 4,547,615 (Mo ₁₂biFe _0.1ni ₈zrCr ₃k _0.2o _xand Mo ₁₂biFe _0.1ni ₈alCr ₃k _0.2o _x), US 4,424,141 (Mo ₁₂biFe ₃co _4.5ni _2.5p _0.5k _0.1o _x+ SiO ₂), DE-A 25 30 959 (Mo ₁₂biFe ₃co _4.5ni _2.5cr _0.5k _0.1o _x, Mo _13.75biFe ₃co _4.5ni _2.5ge _0.5k _0.8o _x, Mo ₁₂biFe ₃co _4.5ni _2.5mn _0.5k _0.1o _xand Mo ₁₂biFe ₃co _4.5ni _2.5la _0.5k _0.1o _x), US 3,911,039 (Mo ₁₂biFe ₃co _4.5ni _2.5sn _0.5k _0.1o _x), DE-A 25 30 959 and DE-A 24 47 825 (Mo ₁₂biFe ₃co _4.5ni _2.5w _0.5k _0.1o _x) in.

Suitable poly-metal deoxide and preparation thereof are also described in US 4,423,281 (Mo ₁₂biNi ₈pb _0.5cr ₃k _0.2o _xand Mo ₁₂bi _bni ₇al ₃cr _0.5k _0.5o _x), US 4,336,409 (Mo ₁₂biNi ₆cd ₂cr ₃p _0.5o _x), DE-A 26 00 128 (Mo ₁₂biNi _0.5cr ₃p _0.5mg _7.5k _0.1o _x+ SiO ₂) and DE-A 24 40 329 (Mo ₁₂biCo _4.5ni _2.5cr ₃p _0.5k _0.1o _x) in.

The particularly preferred catalytic activity poly-metal deoxide comprising molybdenum and other metal of at least one has general formula (Ia):

Mo ₁₂Bi _aFe _bCo _cNi _dCr _eX ¹ _fX ² _gO _y(Ia)，

Wherein:

X ¹=Si, Mn and/or Al,

X ²=Li, Na, K, Cs and/or Rb,

0.2≤a≤1，

0.5≤b≤10，

0≤c≤10，

0≤d≤10，

2≤c+d≤10，

0≤e≤2，

0≤f≤10，

0≤g≤0.5，

The number that y=is determined by chemical valence and the abundance of the element beyond oxygen in (1a) is to realize neutral charge.

Preferably in two kinds of metal Co and Ni, catalytic activity oxide composition only comprises the catalyst (d=0) of Co.X ¹be preferably Si and/or Mn, and X ²be preferably K, Na and/or Cs, wherein X ²be particularly preferably K.

Stoichiometric coefficient a in formula (Ia) is preferably 0.4≤a≤1, particularly preferably 0.4≤a≤0.95.The value of variable b is preferably 1≤b≤5, particularly preferably 2≤b≤4.Stoichiometric coefficient c+d and be preferably 4≤c+d≤8, particularly preferably 6≤c+d≤8.Stoichiometric coefficient e is preferably 0.1≤e≤2, particularly preferably 0.2≤e≤1.Stoichiometric coefficient g is advantageously >=0.Preferably 0.01≤g≤0.5, particularly preferably 0.05≤g≤0.2.

The value of the stoichiometric coefficient y of oxygen is determined to keep neutral charge by cationic chemical valence and abundance.Have mol ratio Co/Ni at least 2:1, preferably at least 3:1, particularly preferably at least the coated catalysts of the present invention of the catalytic activity oxide composition of 4:1 is favourable.It is preferred that only there is Co.

Coated catalysts has carrier (a) and comprises the shell (b) of the catalytic activity poly-metal deoxide containing molybdenum and other metal of at least one.Shell (b) is preferably prepared without pore-forming agent.The use of pore-forming agent can improve the transportation performance in each catalyst granules.But the abrasion resistance of catalyst can reduce largely due to the use of pore-forming agent.Abrasive catalyst can to accumulate in reactor beds and to cause uncontrollable reaction and/or large pressure drop to improve.

Carrier (a) can have rule or irregularly shaped, wherein preferably has the regular shape carrier of obvious surface roughness, as spheroid, cylinder or hollow circular cylinder.Their length is generally 1-10mm.

Carrier material can be porous or atresia.Carrier material is preferably (total pore volume is preferably≤1 volume % based on the volume of carrier) of atresia.The carrier surface roughness improved causes the adhesion of the shell applied improved usually, and can such as be realized by broken material layer.

The surface roughness RZ of carrier (a) is preferably 30-100 μm, and preferred 50-70 μm (uses " the Hommel Tester f ü r from Hommelwerke according to DIN4768 first page " measure).Particularly preferably there is surface roughness and the carrier be made up of the steatite C 220 from CeramTec.

According to the present invention, can use and form and there is rough surface and 1-8mm, preferred 2-6mm by steatite (such as from the C 220 type steatite of CeramTec), particularly preferably basic non-porous spherical carrier (a) of the diameter of 2-3 or 4-5mm.But the cylinder with the length of 2-10mm and the external diameter of 4-10mm is also useful especially as carrier.When ring is as carrier, wall thickness is generally 1-4mm.Preferred annular carrier has the wall thickness of the length of 2-6mm, the external diameter of 4-8mm and 1-2mm.The ring with geometry 7mm × 3mm × 4mm (external diameter × length × internal diameter) is also especially suitable for makes carrier.

Preferred carrier has the shape of hollow circular cylinder, and wherein internal diameter is 0.2-0.8 times of external diameter, and length is 0.2-1.5 times of external diameter.In a particularly preferred embodiment, it is (4-10mm) × (2-8mm) × (1-10mm) that hollow cylindrical carrier (a) has diameter × length × internal diameter.Carrier (a) particularly preferably has diameter × length × internal diameter (4-8mm) × (2-5mm) × (1-5mm).The layer thickness D comprising the shell (b) of the multimetal oxide compositions containing molybdenum and other metal of at least one is generally 50-1000 μm.Preferred 50-800 μm, particularly preferably 50-600 μm, very particularly preferably 80-500 μm.

Coated catalysts is by put on the layer of the poly-metal deoxide comprised containing molybdenum and other metal of at least one by adhesive on carrier and the carrier drying of coating and heat treatment to be prepared.According to the present invention, the poly-metal deoxide particle put on carrier by adhesive has the d of 6-13 μm ₅₀.

Present invention also offers the method preparing coated catalysts, described coated catalysts comprises:

(a) carrier,

B () comprises the shell of the catalytic activity poly-metal deoxide containing molybdenum and other metal of at least one, its mesochite is by the d with 6-13 μm ₅₀poly-metal deoxide particle make,

Described method comprises step:

I () preparation comprises the poly-metal deoxide precursor composition of molybdenum and other metal of at least one,

(ii) formed body is prepared by poly-metal deoxide precursor composition,

(iii) the formed body calcining of poly-metal deoxide precursor composition will be comprised to produce multimetal oxide compositions,

(iv) formed body comprising multimetal oxide compositions is pulverized to form the d with 6-13 μm ₅₀poly-metal deoxide particle,

V carrier metal oxide particle applies by (),

(vi) by the support heat-tr eatment of coating.

In first step (i), preparation comprises the poly-metal deoxide precursor composition of molybdenum and other metal of at least one.

For preparing suitable poly-metal deoxide precursor composition in small, broken bits, the known initial compounds of the elemental constituent beyond the oxygen of required poly-metal deoxide precursor composition is used as raw material with respective stoichiometric proportion, produced closely by these raw materials, dry mixture preferably in small, broken bits, then makes this dry mixture through heat-treated.Source can be oxide or the compound changing into oxide by heating at least in the presence of oxygen.Therefore, except oxide, can use particularly halide, nitrate, formates, oxalates, acetate, carbonate or hydroxide as initial compounds.

Other suitable initial compounds of molybdenum is its oxo-compound (molybdate) or the acid derived from these.

Suitable initial compounds particularly its nitrate of Bi, Cr, Fe and Co.

The tight mixed principle of initial compounds can be carried out with dry form or with the form of the aqueous solution or water slurry.

Water slurry can such as by comprising the solution of at least molybdenum and comprise the aqueous solution merging of all the other metals and prepare.All alkali metal or alkaline-earth metal can be there is in these two kinds of solution.Precipitate by being merged by solution and carry out, this causes the formation of suspension.Temperature in precipitation can be greater than room temperature, preferably 30 DEG C to 95 DEG C, particularly preferably 35 DEG C to 80 DEG C.Then can by the suspension aging specific time at elevated temperatures.The aging time is generally 0-24 hour, preferred 0-12 hour, particularly preferably 0-8 hour.Temperature between aging period is generally 20 DEG C to 99 DEG C, preferably 30 DEG C to 90 DEG C, particularly preferably 35 DEG C to 80 DEG C.Usually by stirring, suspension is mixed between precipitation and aging period.The pH of mixed solution or suspension is generally pH 1 to pH 12, preferred pH 2 to pH 11, particularly preferably pH 3 to pH 10.

Water remove generation solid, which represent the intimate mixture of the metal component added.Drying steps is undertaken by evaporation, spraying dry or freeze-drying etc. usually.Drying is carried out preferably by spraying dry.For this reason, by suspension at elevated temperatures by usual fog-spray nozzle atomization at the temperature of 120 DEG C to 300 DEG C, and desciccate is collected at the temperature of >60 DEG C.Be generally by the residual moisture content at 120 DEG C, spray-dried powders drying measured and be less than 20 % by weight, be preferably less than 15 % by weight, be particularly preferably less than 12 % by weight.

In second step (ii), prepare formed body by poly-metal deoxide precursor composition.

In a further step, spray-dried powders is changed into formed body (catalyst precarsor formed body).Possible shaping assistant (lubricant) is such as water, boron trifluoride or graphite.Based on the composition obtaining catalyst precarsor formed body to be formed, generally add≤10 % by weight, usually≤6 % by weight, usually≤4 % by weight shaping assistants.Above-mentioned addition is generally >0.5 % by weight.Possible lubricating auxiliary agent is such as described in DE 102007005606.Be graphite according to the preferred lubricant of the present invention.

In third step (iii), calcine formed body from poly-metal deoxide precursor composition to form multimetal oxide compositions.

The temperature of calcining usually more than 350 DEG C of catalyst precarsor formed body is carried out.But, during heat treatment process, be usually no more than the temperature of 650 DEG C.According to the present invention, the temperature in heat treatment, advantageously not more than 600 DEG C, preferably more than 550 DEG C, is particularly preferably no more than 500 DEG C.In addition, the temperature of the catalyst precarsor formed body Heat Treatment in the inventive method is preferably more than 380 DEG C, advantageously more than 400 DEG C, particularly advantageously more than 420 DEG C, very particularly preferably more than 440 DEG C.Heat treatment also can be divided into multiple time period.Such as, first at 150-350 DEG C, can heat-treat at the temperature of preferred 220-280 DEG C, subsequently at 400-600 DEG C, heat-treat at the temperature of preferred 430-550 DEG C.Multiple hours (being usually greater than 5 hours) is carried out in the heat treatment of catalyst precarsor formed body usually.Heat treated total duration usually extends to and is greater than 10 hours.Usually the processing time of 45 hours or 35 hours is no more than in the heat treatment of catalyst precarsor formed body.Be generally total processing time and be less than 30 hours.Processing time preferred development in the heat treatment of catalyst precarsor formed body preferably more than the temperature of 500 DEG C and in the temperature range of >=400 DEG C is to 5-30 hour.

The calcining (hereinafter also referred to as catabolic phase) of catalyst precarsor formed body can under an inert gas or under oxidizing atmosphere be as air (mixture of inert gas and oxygen) or at reducing atmosphere (such as inert gas, NH ₃, CO and/or H ₂or the mixture of methane) under carry out.Self-evidently, heat treatment also can under reduced pressure be carried out.The heat treatment of catalyst precarsor formed body can be carried out in principle in polytype stove, such as can heated convection room, board-like stove, rotary tube furnace, belt calcinatory or shaft (tower) furnace.The heat treatment of catalyst precarsor formed body preferably as in DE-A 10046957 and WO 02/24620 carry out in the belt calciner recommended.The heat treatment of catalyst precarsor formed body below 350 DEG C is usually along with the thermal decomposition in the elemental constituent source of catalyst needed for contained in catalyst precarsor formed body.This catabolic phase occurs usually in the methods of the invention during being heated to the temperature of <350 DEG C.

In the 4th step (iv), the calcining formed body comprising poly-metal deoxide is pulverized to form the d with 6-13 μm ₅₀poly-metal deoxide particle.Any suitable grinding machine can be used herein.

Be crushed to this granularity preferably to carry out in grading mill (Sichterm ü hlen).These are have rotor strike mill (Rotorprallm ü hlen) being integrated in static state in grinding machine or dynamic classification device.Comminution instrument is place the rotor with shock plate (Schlagplatten) outside.When having the grinding machine of static rank device, rotor is generally level, and when having the grinding machine of dynamic classification device, rotor is vertically arranged.It rotates with the peripheral speed reaching 120m/s.Product to be comminuted is introduced in rotor in central authorities, is ground by impact components, then impinge upon and above also occur there to grind further around the grinding rail (Mahlbahn) of rotor with one heart.After repeatedly standing stress, the air-flow being aspirated through grinding machine by particle transport in graded region.When having the grinding machine of static rank device, its by the orifice plate being positioned at rotor downstream with and subsequent air blast form.Air whirl is formed in orifice plate upstream.Centrifugal force and the carrying capacity of gas act on the particle of circular rotating.Carrying capacity is larger for bulky grain, and these particles return in disintegrating area, and carrying capacity is larger when relatively fine particle.The latter as ground material along with air-flow leaves grinding machine by orifice plate.When having the modern grinding machine of dynamic classification device, classification not in air whirl, but is carried out in clasfficiator wheel.It is made up of swiveling wheel usually, in swiveling wheel, there is intermediate space between ridge (Stegen).The particle carried between layers by pulverizing gas is accelerated along circuit orbit and is separated with carrying capacity by centrifugal force.Be separated wheel and allow separation more sharply more obvious than static rank device.

The average fineness of size distribution and steepness are mainly by following parameter influence: the type of the peripheral speed (rotating speed) of grinding rotor, the number of impact components and type, grinding rail, centrifugal acceleration (rotating speed)/orifice plate diameter, gas throughput, the product throughput of clasfficiator wheel.

In the 5th step (v), carrier is used poly-metal deoxide particle coating.

The carrier material being suitable for coated catalysts of the present invention is aluminium oxide, silica, zirconium dioxide, the carborundum of porous or preferred atresia, or silicate is as magnesium silicate or alumina silicate (such as from C 220 grades of steatites of CeramTec).Carrier material is chemically inert, and this means under the reaction condition of oxidative dehydrogenation, and they do not have catalytic activity for the conversion of the organic component be included in starting gas.

Carrier material can be porous or atresia.Carrier material is preferably (total pore volume is preferably≤1 volume % based on the volume of carrier) of atresia.

Preferred carrier has the form of hollow circular cylinder, wherein internal diameter be external diameter 0.2-0.8 doubly and length be the 0.5-2.5 of external diameter doubly.

Preferred hollow circular cylinder as carrier has the length of 2-10mm and the external diameter of 4-10mm.In addition, wall thickness is preferably 1-4mm.Particularly preferably annular carrier has the wall thickness of the length of 2-6mm, the external diameter of 4-8mm and 1-2mm.An example is for having the ring of geometry 7mm × 3mm × 4mm (external diameter × length × internal diameter) as carrier.

The layer thickness D comprising the multimetal oxide compositions of molybdenum and other metal of at least one is generally 5-1000 μm.Preferred 10-800 μm, particularly preferably 50-600 μm, very particularly preferably 80-500 μm.

The poly-metal deoxide comprising molybdenum and other metal of at least one is put on carrier surface and can carry out in the mode corresponding to method described in prior art, such as, method as described in US-A 2006/0205978 and EP-A 0 714 700.

Generally speaking, by liquid adhesive, composition in small, broken bits is put on the surface of carrier surface or ground floor.Possible liquid adhesive is such as water, organic solvent or organic substance (such as organic solvent) solution in water or in organic solvent.

The solution comprising 20-95 % by weight water and 5-80 % by weight organic compound is particularly advantageously used as liquid adhesive.The content of organics of aforesaid liquid adhesive is preferably 10-50 % by weight, particularly preferably 10-30 % by weight.

Usually preferred under atmospheric pressure (1atm) boiling point or sublimation temperature be >=100 DEG C, the preferably >=organic bond of 150 DEG C or adhesive component.Below the maximum calcination temperature that this kind of organic bond or adhesive component boiling point at atmosheric pressure or sublimation point very particularly preferably use simultaneously during the preparation containing molybdenum poly-metal deoxide in small, broken bits.This maximum calcination temperature is generally≤and 600 DEG C, be usually≤500 DEG C.

Particularly preferred liquid adhesive is the solution comprising 20-95 % by weight water and 5-80 % by weight glycerine.Glycerol content in these aqueous solution is preferably 5-50 % by weight, particularly preferably 8-35 % by weight.

Containing the applying of molybdenum poly-metal deoxide in small, broken bits by will to be dispersed in containing the composition in small, broken bits of molybdenum multi-metal oxide in liquid adhesive and by gained suspension spray to stirring and the carrier of optional heat carrying out, as described in DE-A 1642921, DE-A 2106796 and DE-A 2626887.After spraying completes, the moisture of gained coated catalysts can by making hot-air be reduced by catalyst as described in DE-A 2909670.

But, preferably first carrier liquid adhesive is soaked, by wetting carrier is rolled in composition in small, broken bits, the composition in small, broken bits of poly-metal deoxide is put on the surface of the carrier soaked with adhesive subsequently.For realizing required layer thickness, the carrier with the first coating preferably repeatedly, that is, soaks by said method again, then applies by contacting with dry composition in small, broken bits.

In order to carry out the method with commercial scale, wise is use method disclosed in DE-A 2909671, but preferably use the adhesive recommended in EP-A 714700, that is, carrier to be coated is introduced in the rotary container (such as swivel plate or coating cylinder) of preferred angled (inclination angle is generally 30-90 DEG C).Hollow cylindrical carrier is delivered to below two metering devices in succession arranged with specific range each other by rotary container.First in two metering devices is advantageously nozzle, and the carrier rolled in swivel plate is also soaked by liquid adhesive to be used spraying in a controlled manner by this nozzle.Outside the atomizer (atomizing) cone that second metering device is positioned at the liquid adhesive sprayed into and for such as feeding composition in small, broken bits by vibration chute.Carrier wetting to controllably obtains the active compound powder fed, and the outer surface that then this powder is crushed on cylindrical vector by rolling movement obtains adhering to shell.

If necessary, the carrier making to have in this way the first coating is wetting to controllably can obtain another layer of composition layer in small, broken bits in the processes such as motion further by nozzle again during rotary course subsequently.Usually intermittent drying is not needed.Liquid adhesive partially or completely remove by finally provide heat and carry out, such as by with hot gas as N ₂or air contacts and carries out.In a particularly preferred embodiment of said method, the coated catalysts with the shell be made up of the layer of two or more different components can be prepared in one operation.Significantly, the method make successive layer each other and on carrier surface ground floor adhesion be entirely satisfactory.This is also applicable to the situation of annular carrier.

In the 6th step (vi), by the support heat-tr eatment of coating.

What cause adhesion promoter removes required temperature below the maximum calcination temperature of catalyst, is generally 200 DEG C to 600 DEG C.Preferably catalyst is heated to 240 DEG C to 500 DEG C, particularly preferably the temperature of 260 DEG C to 400 DEG C.The time of removing adhesion promoter can be multiple hours.Usually catalyst is heated to said temperature 0.5-24 hour to remove adhesion promoter.This time is preferably 1.5-8 hour, particularly preferably 2-6 hour.Gas flowing around catalyst can promote removing of adhesion promoter.Gas is preferably air or nitrogen, particularly preferably air.Removing in the baking oven that can such as flow through at gas of adhesion promoter, or carry out in suitable drying equipment is as band drier.

oxidative dehydrogenation (ODH)

Present invention also offers coated catalysts of the present invention and 1-butylene and/or 2-butylene oxidation-dehydrogenation are being become the purposes in the method for butadiene.Catalyst of the present invention demonstrates high activity, particularly also demonstrates the high selectivity being formed 1,3-butadiene by 1-butylene and 2-butylene, and high wear resistance.

Present invention also offers method n-butene oxidative dehydrogenation being become butadiene, wherein will comprise the starting gas mixture of n-butene and oxygen-containing gas and optionally other inert gas or steam, and contact at the temperature of 220-490 DEG C in fixed bed reactors with the coated catalysts of the present invention arranged with stationary catalyst bed.The temperature provided relates to the heat-transfer medium temperature at the heat transfer medium inlet place on reactor.

The reaction temperature of oxidative dehydrogenation is controlled by the heat transfer medium be positioned at around reaction tube usually.As this liquid heat-transfer medium, can such as use salt as the melt of potassium nitrate, potassium nitrite, natrium nitrosum and/or sodium nitrate, and metal is as the melt of the alloy of sodium, mercury and various metal.But, also can use ionic liquid or heat-transfer oil.The temperature of heat transfer medium is 220-490 DEG C, preferred 300-450 DEG C, particularly preferably 350-420 DEG C.

Because the reaction occurred has exothermal nature, during reaction in the particular section of inside reactor, temperature can form focus higher than the temperature of heat transfer medium.Position and the magnitude of focus are determined by reaction condition, but also by the thinner ratio of catalyst layer or mist by adjusting.Difference between hot(test)-spot temperature and heat-transfer medium temperature is generally 1-150 DEG C, preferred 10-100 DEG C, particularly preferably 20-80 DEG C.The temperature of catalyst bed end usually than the temperature height 0-100 DEG C of heat transfer medium, preferred high 0.1-50 DEG C, particularly preferably high 1-25 DEG C.

Oxidative dehydrogenation in the known all fixed bed reactors of prior art, such as, in board-like stove, fixed-bed tube reactor or shell-tube type reactor, or can be carried out in plate type heat exchanger reactor.Preferred shell-tube type reactor.

In addition, the catalyst bed of installing in the reactor can be made up of single district or 2 or more district.These districts can be made up of pure catalyst or with not diluting with starting gas or by the material that the product gas component that this reaction is formed reacts.In addition, catalyst zone can be made up of full active catalyst or support type coated catalysts.

As starting gas, pure n-butene (1-butylene and/or cis-/Trans-2-butene) can be used, also can use the admixture of gas comprising butylene.Such mixture can such as be obtained by the Non-oxidative dehydrogenation of normal butane.Also can use and comprise the cut of n-butene (1-butylene and/or 2-butylene) as key component, it is by the C from cracking naphtha ₄cut is by removing butadiene and isobutene and obtaining.In addition, the admixture of gas comprising pure 1-butylene, cis-2-butene, Trans-2-butene or its mixture obtained by the dimerization of ethene also can be used as starting gas.Also the admixture of gas comprising n-butene obtained by fluid catalytic cracking (FCC) can be used as starting gas.In an embodiment of the inventive method, the starting gas mixture comprising n-butene is obtained by the Non-oxidative dehydrogenation of normal butane.Based on normal butane used, high butadiene yield obtains by being combined with the oxidative dehydrogenation of formed n-butene by nonoxidation catalytic dehydrogenation.

The nonoxidation catalytic dehydrogenation of normal butane obtains comprising the admixture of gas of butadiene, 1-butylene, 2-butylene and unreacted normal butane and secondary component.Common secondary component is hydrogen, steam, nitrogen, CO and CO ₂, methane, ethane, ethene, propane and propylene.The composition leaving the admixture of gas of the first dehydrogenation zone can be depending on the operator scheme of dehydrogenation and greatly changes.Therefore, when dehydrogenation is carried out along with introducing oxygen and other hydrogen, product gas mixture has quite high steam and oxycarbide content.Do not introducing in the operator scheme of oxygen, the product gas mixture from Non-oxidative dehydrogenation has quite high hydrogen content.

Product gas flow from the Non-oxidative dehydrogenation of normal butane comprises 0.1-15 volume % butadiene, 1-15 volume %1-butylene, 1-25 volume %2-butylene (cis/trans-2-butylene), 20-70 volume % normal butane, 1-70 volume % steam, 0-10 volume % low boiling hydrocarbon (methane, ethane, ethene, propane and propylene), 0.1-40 volume % hydrogen, 0-70 volume % nitrogen and 0-5 volume % oxycarbide usually.

Product gas flow from Non-oxidative dehydrogenation can be fed in oxidative dehydrogenation without further post processing.

In addition, any impurity can be present in the starting gas of oxidative dehydrogenation not suppress the amount of effect of the present invention.Preparing in butadiene by n-butene (1-butylene and cis-/Trans-2-butene), the impurity that can mention is saturated and unsaturated, branching and non-branching hydrocarbon, such as methane, ethane, ethene, acetylene, propane, propylene, propine, normal butane, iso-butane, isobutene, pentane and diene are as 1,2-butadiene.The amount of impurity is generally 70% or less, and preferably 30% or less, more preferably 10% or less, particularly preferably 1% or less.The concentration in starting gas with the linear single olefin (n-butene and more higher homologue) of 4 or more carbon atoms is not limited with any ad hoc fashion; It is generally 35.00-99.99 volume %, preferred 71.00-99.0 volume %, even more preferably 75.00-95.0 volume %.

In order to oxidative dehydrogenation is carried out in the conversion completely with butylene, need the oxygen with at least 0.5: the admixture of gas of n-butene mol ratio.Preferably with the oxygen of 0.55-10: n-butene compares work.For arranging this value, can by starting gas and oxygen or oxygen-containing gas as air and optional inert gas or steam in addition.Then gained oxygen-containing gas mixture is fed in oxidative dehydrogenation.

The gas comprising molecular oxygen is greater than 10 volume % for usually comprising, and is preferably greater than 15 volume %, even more preferably greater than the gas of 20 volume % molecular oxygens, and especially preferably air.The upper limit of molecular oxygen content is generally 50 volume % or less, preferably 30 volume % or less, even more preferably 25 volume % or less.In addition, any inert gas can comprise in the gas of molecular oxygen not suppress the amount of effect of the present invention to be present in.As possible inert gas, nitrogen, argon gas, neon, helium, CO, CO can be mentioned ₂and water.When nitrogen, the amount of inert gas is generally 90 volume % or less, preferably 85 volume % or less, even more preferably 80 volume % or less.When being different from the component of nitrogen, they are usually with 10 volume % or less, and preferably 1 volume % or less amount exist.If this quantitative change obtains too large, then required oxygen is provided to become more and more difficult to reaction.

In addition, can with by starting gas with comprise molecular oxygen gas composition mist together with comprise inert gas as nitrogen and water (as steam).There is nitrogen to arrange oxygen concentration and to prevent the formation of explosive gas mixture, be equally applicable to steam.Also there is steam to control the carbonization of catalyst and to remove reaction heat.Water (as steam) and nitrogen to be preferably mixed in mist and to introduce in reactor.When being introduced in reactor by steam, preferably the introduction volume introduced based on above-mentioned starting gas is 0.2-5.0 (parts by volume), preferred 0.5-4, the even more preferably ratio of 0.8-2.5.When being introduced in reactor by nitrogen, preferably the introduction volume introduced based on above-mentioned starting gas is 0.1-8.0 (parts by volume), preferred 0.5-5.0, the even more preferably ratio of 0.8-3.0.

The content of starting gas in mist comprising hydrocarbon is generally 4.0 volume % or more, preferably 6.0 volume % or more, even more preferably 8.0 volume % or more.On the other hand, the upper limit is 20 volume % or less, preferably 16.0 volume % or less, even more preferably 13.0 volume % or less.In order to avoid the formation of explosive gas mixture safely, before obtaining mist, first being introduced by nitrogen in starting gas or introducing comprises in the gas of molecular oxygen, by starting gas with comprise the gas and vapor permeation of molecular oxygen to obtain mist, then preferably introduces this mist.

During stable operation, the time of staying is in the reactor not limited with any ad hoc fashion in the present invention, but lower limit is generally 0.3 second or more, preferably 0.7 second or more, even more preferably 1.0 seconds or more.The upper limit is 5.0 seconds or less, preferably 3.5 seconds or less, even more preferably 2.5 seconds or less.The throughput of mist is 500-8000h with the ratio of the amount of the catalyst of inside reactor ^-1, preferred 800-4000h ^-1, even more preferably 1200-3500h ^-1.In stable operation, butylene air speed is on a catalyst (with g _butylene/ (g _catalyst* hour expression) be generally 0.1-5.0h ^-1, preferred 0.2-3.0h ^-1, even more preferably 0.25-1.0h ^-1.The volume of catalyst and quality are based on the integer catalyst be made up of carrier and active compound.

the post processing of product gas flow

The product gas flow leaving oxidative dehydrogenation comprises butadiene, usually also comprises unreacted normal butane and iso-butane, 2-butylene and steam.As secondary component, it usually comprises carbon monoxide, carbon dioxide, oxygen, nitrogen, methane, ethane, ethene, propane and propylene, possibility steam and is called the oxygen-containing hydrocarbon of oxygenate.Generally speaking, it only comprises 1-butylene and the isobutene of small scale.

The product gas flow leaving oxidative dehydrogenation such as can comprise 1-40 volume % butadiene, 20-80 volume % normal butane, 0-5 volume % iso-butane, 0.5-40 volume %2-butylene, 0-5 volume %1-butylene, 0-70 volume % steam, 0-10 volume % low boiling hydrocarbon (methane, ethane, ethene, propane and propylene), 0-40 volume % hydrogen, 0-30 volume % oxygen, 0-70 volume % nitrogen, 0-10 volume % oxycarbide and 0-10 volume % oxygenate.Oxygenate can be such as formaldehyde, furans, acetic acid, maleic anhydride, formic acid, methacrolein, methacrylic acid, crotonaldehyde, crotonic acid, propionic acid, acrylic acid, methyl vinyl ketone, styrene, benzaldehyde, benzoic acid, phthalic anhydride, Fluorenone, anthraquinone and butyraldehyde.

Some oxygenate can oligomeric and dehydrogenation further on catalyst surface and in post processing, thus forms the deposit comprising carbon, hydrogen and oxygen, hereinafter referred to carbonaceous material.Interruption during these deposits can cause the method to operate, with cleaning and regeneration, is therefore undesirable.The typical precursor of carbonaceous material comprises styrene, Fluorenone and anthraquinone.

Product gas flow in the temperature of reactor exit close to the temperature of catalyst bed end.Then product gas flow is made to reach 150-400 DEG C, preferred 160-300 DEG C, particularly preferably the temperature of 170-250 DEG C.The pipeline insulation (isolieren) that product gas flow can be flow through to maintain the temperature in required scope, but preferably uses heat exchanger.This heat exchanger system can be any type, and condition is that the temperature of product gas remains on desired level by this system.As the example of heat exchanger, spiral heat exchanger, plate type heat exchanger, Dual-tube heat exchanger, multi-pipe heat exchanger, boiler spiral heat exchanger, boiler jacket heat-exchanger, liquid/liquid contact heat exchanger, air heat exchanger, direct contact heat transfer device and fined tube exchanger can be mentioned.Owing to being included in, a part in product gas is high boiling point by-products produced may be precipitated to time temperature required product gas temperature being arranged, and heat exchanger system preferably should have 2 or more heat exchangers.When 2 that provide or more heat exchangers be arranged in parallel and therefore make the product gas that obtains in heat exchanger separately cooling, the high boiling point by-products produced amount deposited in heat exchanger reduces, and therefore can extend the operating time of heat exchanger.As the replacement scheme of said method, 2 that provide or more heat exchangers can be arranged in parallel.Product gas is fed one or more, but in not all heat exchanger, and can by other heat exchanger rotation of these heat exchangers after the specific operation time.In the method, sustainable cooling, recyclable a part of reaction heat and therewith concurrently, can remove that to be deposited in one of heat exchanger high boiling point by-products produced.As organic solvent as mentioned above, can use any non-limiting solvent, condition is that it can dissolve high boiling point by-products produced, such as aromatic hydrocarbon solvent, such as toluene, dimethylbenzene etc., or basic aqueous solvent, such as sodium hydrate aqueous solution.

If product gas flow comprises the oxygen exceeding only little trace, then can carry out the processing step removing residual oxygen from product gas flow.Residual oxygen can be disturbed to this degree: it can cause Butadiene Peroxide in processing step subsequently formed and can serve as the initator of polymerisation.Unstable 1,3-butadiene can form dangerous Butadiene Peroxide in the presence of oxygen.This peroxide is viscous liquid.Their density is higher than butadiene.Because they are also only slightly soluble in liquid 1,3-butadiene, they settle in the bottom of reservoir vessel.Although their chemical reactivity is lower, peroxide is very unstable compound, and they spontaneously can decompose at the temperature of 85-110 DEG C.Special danger is the height vibrations sensitiveness of peroxide, and it explodes with volatile power.Especially by there is the risk that forms polymer during separated butadiene and the polymer deposits (formation of " puffed rice ") in tower can being caused in that case.Removing of oxygen is preferably carried out immediately after oxidative dehydrogenation.Generally speaking, carry out the catalytic combustion stage for this reason, wherein oxygen in the presence of a catalyst with the hydrogen reaction that adds in this stage.This makes oxygen content be down to little trace.

Then make from O ₂the product gas removing the stage reach with to temperature levels identical described in ODH reactor downstream region.The heat exchanger that is cooled through of Compressed Gas carries out, and described heat exchanger can such as be configured to shell and tube exchanger, spiral heat exchanger or plate type heat exchanger.The heat herein removed is preferred for the heat integration in method.

Subsequently by cooling from product gas flow separating most higher boiling secondary component and most of water.This separation is preferably carried out in quenching.This quenching can comprise one or more stage.Preferred use wherein makes product gas directly contact with cooling medium, the method cooled thus.Cooling medium not by any special restriction, but preferably uses water or alkaline aqueous solution.This obtains normal butane, 1-butylene, 2-butylene, butadiene, possibility oxygen, hydrogen, steam and methane, ethane, ethene, propane and propylene, isobutene, oxycarbide and inert gas stay air-flow wherein on a small quantity.In addition, the trace high boiling component be separated not yet quantitatively in quenching may be left in this product gas flow.

Subsequently the product gas flow from quenching is compressed at least one compression stage, cool subsequently, therefore condensation go out condensate stream staying that at least one comprises water comprise normal butane, 1-butylene, 2-butylene, butadiene, may hydrogen, steam and a small amount of methane, ethane, ethene, propane and propylene, isobutene, oxycarbide and inert gas, may the air-flow of oxygen and hydrogen.Compression can be carried out in one or more stage.On the whole, air-flow is compressed to the pressure of 3.5-20 bar (definitely) from the pressure of 1.0-4.0 bar (definitely).Be cooling stage after each compression stage, wherein air-flow be cooled to the temperature of 15-60 DEG C.Therefore, when the multistage is compressed, condensate stream can comprise multiple stream.Condensate stream comprises at least 80 % by weight usually, preferably at least 90 % by weight water, and comprises a small amount of low-boiling-point substance further, C ₄hydrocarbon, oxygenate and oxycarbide.

Suitable compressor is such as turbo-compressor, rolling piston compressor and reciprocating-piston compressor.Compressor can such as be driven by motor, expander or gas turbine or steamturbine.The typical compression ratio (outlet pressure: inlet pressure) of every compressor stage depends on that structure type is 1.5-3.0.The heat exchanger that is cooled through of Compressed Gas carries out, and described heat exchanger can such as be configured to shell and tube exchanger, spiral heat exchanger or plate type heat exchanger.In heat exchanger, cooling agent used is cooling water or heat-transfer oil.In addition, the Air flow adopting air blast is preferably used.

To comprise butadiene, butylene, butane, inert gas and may oxycarbide, oxygen, hydrogen and low boiling hydrocarbon (methane, ethane, ethene, propane, propylene) and a small amount of oxygenate stream feed process further as initial stream.

Low boiling secondary component is separated by conventional separation methods as distillation, rectifying, film method, absorption or absorption are carried out from product gas flow.

For isolating any hydrogen comprised in product gas flow, can make product gas mixture optionally after (such as in heat exchanger) cooling by film, only molecular hydrogen can pass through this film and this film is configured to pipe usually.The molecular hydrogen separated so if necessary can at least in part in hydrogenation or pass into another purposes, such as, for producing electric energy in a fuel cell.

Be included in carbon dioxide in product gas flow by CO ₂drechsel system is separated.Can be independent combustion phases before carbon dioxide washer, become carbon dioxide at this stage co selective oxidation.

In a preferred embodiment of the method, in absorption/desorption circulation, isolate not condensable or low-boiling point gas component if hydrogen, oxygen, oxycarbide, low boiling hydrocarbon (methane, ethane, ethene, propane, propylene) and inert gas are as possible nitrogen by higher boiling absorbing medium, obtain substantially by C ₄the C of hydrocarbon composition ₄product gas flow.Generally speaking, C ₄product gas flow comprises at least 80 volume %, preferably at least 90 volume %, particularly preferably at least 95 volume %C ₄hydrocarbon, especially normal butane, 2-butylene and butadiene.

For this reason, after previous water removes, product gas flow is made to contact with inertia absorbing medium in the absorption stage and make C ₄hydrocarbon is absorbed in inertia absorbing medium, obtains being loaded with C ₄absorbing medium and the tail gas comprising remaining gas component of hydrocarbon.In desorption phase, C ₄hydrocarbon again discharges from absorbing medium.

Absorption stage can carry out in any suitable absorption tower well known by persons skilled in the art.Absorb by simply product gas flow being undertaken by absorbing medium.But it also can carry out in tower or in rotary absorber.Absorption can and flow, adverse current or cross-flow carry out.Absorb preferred adverse current to carry out.Suitable absorption tower is such as having the plate column of bubble cap plate, centrifugal column plate and/or sieve plate, and having structured packing such as specific area is 100-1000m ²/ m ³sheet metal filler as the tower of 250 Y, and the tower with random packing.But trickling tower and spray column, graphite block absorber, surface absorber are as thick film absorber and film absorption device, and rotary column, scrubber, intersection sprayer-washer and rotary washer are also fine.

In one embodiment, the stream comprising butadiene, butylene, butane and/or nitrogen and possibility oxygen, hydrogen and/or carbon dioxide is fed in the lower area on absorption tower.In the upper area on absorption tower, introduce the stream comprising solvent and optional water.

Higher boiling non-polar solven is generally, C to be separated out in this solvent for the inertia absorbing medium in the absorption stage ₄hydrocarbon mixture has the solubility obviously larger than remaining gas component to be separated.Suitable absorbing medium is suitable non-polar organic solvent, such as C ₈-C ₁₈aliphatic alkanes, or aromatic hydrocarbon, such as from alkane distillation middle oil fraction, toluene or there is the ether of bulky group, or the mixture of these solvents; Can to adding polar solvent as 1,2-repefral in these.Other suitable absorbing mediums are benzoic ether and phthalic acid and straight chain C ₁-C ₈the ester of alkanol and heat-transfer oil are as biphenyl and diphenyl ether, their chlorinated derivatives and triaryl alkene.Applicable absorbing medium is a mixture for biphenyl and diphenyl ether, preferably has azeotropic composition those, such as commercially available this solvent mixture usually comprises 0.1-25 % by weight repefral.

Suitable absorbing medium is octane, nonane, decane, hendecane, dodecane, tridecane, the tetradecane, pentadecane, hexadecane, heptadecane and octadecane, or obtained by oil plant stream comprise the cut of above-mentioned linear paraffinic hydrocarbons as key component.

In a preferred embodiment, paraffins mixture is as the tetradecane (industrial C ₁₄-C ₁₇cut) as absorption solvent.

At top, absorption tower, take out substantially comprise inert gas, oxycarbide, may butane, butylene as 2-butylene and butadiene, may oxygen, hydrogen and low boiling hydrocarbon (as methane, ethane, ethene, propane, propylene) and steam waste gas streams.This stream partly can be fed ODH reactor or O ₂remove in reactor.This can make the incoming flow of ODH reactor be adjusted to required C ₄hydrocarbon content.

C will be loaded with ₄the solvent stream of hydrocarbon is introduced in desorber.According to the present invention, all tower internals well known by persons skilled in the art are all suitable for this object.In a method scheme, desorption procedure is undertaken by the step-down of the solvent of institute's load and/or heating.Preferred method scheme is introduced by stripping stream and/or fresh stream introduced the bottom of desorption device.Poor containing C ₄the solvent of hydrocarbon can be used as during mixture feeds and be separated together with the steam (water) of condensation, makes water and separated from solvent.All devices well known by persons skilled in the art all can be used for this object.In addition, the water gone out by separated from solvent can be used to produce stripped vapor.

Preferred use 70-100 % by weight solvent and 0-30 % by weight water, particularly preferably 80-100 % by weight solvent and 0-20 % by weight water, particularly 85-95 % by weight solvent and 5-15 % by weight water.The absorbing medium be reproduced in desorption phase was recycled in the absorption stage.

Being separated usually is not very completely, therefore depends on the type of separation, C ₄can exist on a small quantity in product gas flow or only trace other gas component, particularly high boiling hydrocarbon.The burden of processing step is subsequently also reduced by the reduction being separated the volume flow produced.

The basic C be made up of as 2-butylene and butadiene normal butane, butylene ₄product gas flow comprises 20-80 volume % butadiene, 20-80 volume % normal butane, 0-10 volume %1-butylene and 0-50 volume %2-butylene usually, and wherein total amount adds up to 100 volume %.In addition, a small amount of iso-butane can be comprised.

Subsequently can by C ₄product gas flow is separated into the stream be substantially made up of normal butane and 2-butylene and the stream comprising butadiene by extractive distillation.The basic stream be made up of normal butane and 2-butylene can be recycled to the C of ODH reactor whole or in part ₄in charging.Because the butylene isomer in this recycle stream is made up of 2-butylene substantially, and these 2-butylene usually than 1-butylene more slowly oxidative dehydrogenation become butadiene, this recycle stream can be made to stand method for catalytically isomerizing before in introducing ODH reactor.In this catalysis process, the isomeric distribution corresponding to the isomeric distribution existed in thermodynamical equilibrium can be set.

Extractive distillation can such as " und Kohle-Erdgas-Petrochemie ", the 34th (8) volume, 343-346 page, or " Ullmanns der Technischen Chemie ", the 9th volume, 1975 the 4th edition, carry out described in 1-18 page.For this reason, C is made ₄product gas flow in extraction section with extractant, the contact of preferred 1-METHYLPYRROLIDONE (NMP)/aqueous mixtures.Extraction section configures to comprise column plate, random packing element or structured packing as the form of the scrubbing tower of internals usually.It usually has 30-70 theoretical tray thus realizes enough good centrifugation.Scrubbing tower preferably has the back scrubbing district at top of tower.This back scrubbing district is used for reclaiming by liquid hydrocarbon reflux the extractant comprised in the gas phase, for this reason by overhead fraction condensation in advance.C in extractant and extraction section charging ₄the mass ratio of product gas flow is generally 10:1-20:1.Extractive distillation is preferably at 100-250 DEG C, and the particularly bottom temp of 110-210 DEG C, carries out under the pressure of the head temperature of 10-100 DEG C, particularly 20-70 DEG C and 1-15 bar, particularly 3-8 bar.Extraction distillation column preferably has 5-70 theoretical tray.

The extractant be applicable to is butyrolactone; nitrile is as acetonitrile, propionitrile, methoxypropionitrile; ketone is as acetone; furfural; the lower aliphatic acid amides that N-alkyl replaces is as dimethyl formamide, DEF, dimethylacetylamide, diethyl acetamide, N-formyl-morpholine, and the cyclic amides (lactams) that N-alkyl replaces is as N-alkyl pyrrolidone, especially 1-METHYLPYRROLIDONE (NMP).The lower aliphatic acid amides that usual use alkyl replaces or the cyclic amides that N-alkyl replaces.Particularly advantageously dimethyl formamide, acetonitrile, furfural and particularly NMP.

But, also these extractants mixture to each other can be used, the mixture of such as NMP and acetonitrile, the mixture of these extractants and cosolvent and/or tertbutyl ether such as methyl tertiary butyl ether(MTBE), ethyl tert-butyl ether (ETBE), propyl group tertbutyl ether, normal-butyl tertbutyl ether or isobutyl group tertbutyl ether.Particularly suitable extractant is NMP, preferred aqueous solutions form, preferably has 0-20 % by weight water, particularly preferably has 7-10 % by weight water, particularly has 8.3 % by weight water.

Top product stream from extraction distillation column substantially comprises butane and butylene and a small amount of butadiene and takes out with gas or liquid form.Generally speaking, the stream substantially comprising normal butane and 2-butylene comprises 50-100 volume % normal butane, 0-50 volume %2-butylene and other component of 0-3 volume % as iso-butane, isobutene, propane, propylene and C ₅ ⁺hydrocarbon.

In the bottom of extraction distillation column, obtain comprising extractant, water, butadiene and fraction butylene and butane stream and fed in destilling tower.In this way, butadiene is obtained at top or as side-draw stream.Obtain in the bottom of destilling tower the stream comprising extractant and water, the composition wherein comprising the stream of extractant and water corresponds to the composition introduced in extraction.The stream comprising catalyst and water is preferably recycled in extractive distillation.

Extractant solution is transferred in desorption zone, there butadiene is desorbed from extraction solution.Desorption zone can such as to have 2-30, and the scrubbing tower form configuration in a preferred 5-20 theoretical tray and optional back scrubbing district, back scrubbing district such as has 4 theoretical trays.This back scrubbing district is used for reclaiming by liquid hydrocarbon reflux the extractant comprised in the gas phase, for this reason, by overhead fraction condensation in advance.Structured packing, column plate or random packing is provided as internals.Distillation, preferably at 100-300 DEG C, is carried out under the head temperature of the particularly bottom temp of 150-200 DEG C and 0-70 DEG C, particularly 10-50 DEG C.Pressure in destilling tower is preferably 1-10 bar.Generally speaking, compared with extraction section, in desorption zone, there is lower pressure and/or higher temperature.

Needed for obtaining at the top of tower, product stream comprises 90-100 volume % butadiene, 0-10 volume %2-butylene and 0-10 volume % normal butane and iso-butane usually.For butadiene of purifying further, can carry out as further distillation described in the prior.

The present invention is set forth by following examples.

Embodiment

Catalyst synthesizes:

Prepare 2 kinds of solution A and B.

Solution A:

3200g water is put into 10 liters of Stainless steel basins.While being stirred by anchor agitator, 5.2g KOH solution (32 % by weight KOH) is added in the water originally loaded.Solution is heated to 60 DEG C.Then once added 1066g Ammoniun Heptamolybdate Solution ((NH through 10 minutes a little ₄) ₆mo ₇o ₂₄* 4H ₂o, 54 % by weight Mo).By other for gained suspension agitation 10 minutes.

Solution B:

1771g cobalt nitrate (II) solution (12.3 % by weight Co) is put into 5 liters of Stainless steel basins and is heated to 60 DEG C, stirs (anchor agitator) simultaneously.Then once add 645g ferric nitrate (III) solution (13.7 % by weight Fe) through 10 minutes a little, keep this temperature simultaneously.The solution formed is stirred other 10 minutes.Then add 619g bismuth nitrate solution (10.7 % by weight Bi), keep this temperature simultaneously.After other 10 minutes of stirring, once add the solid nitric acid chromium (III) of 109g a little, and the dark red solution formed is stirred other 10 minutes.

The temperature of maintenance 60 DEG C while, solution B is pumped in solution A through 15 minutes by peristaltic pump.During adding and thereafter, stirred the mixture by super mixer (Ultra-Turrax).After interpolation completes, mixture is stirred other 5 minutes.

By gained suspension in from the spray dryer (fog-spray nozzle No.FOA1, rotating speed: 25000rpm) of NIRO through 1.5 hours spraying dry.During this period the temperature of initial charge is remained on 60 DEG C.The gas inlet temperature of spray dryer is 300 DEG C, and gas outlet temperature is 110 DEG C.

Gained powder is mixed with 1 % by weight graphite, in the pressure system twice of 9 bar, and is pulverized by the sieve of the mesh with 0.8mm.Again comminution of material is mixed with 2 % by weight graphite and by Kilian S100 tablet press machine mixture suppressed and obtain 5 × 3 × 2mm ring.

By (500g) calcining in batches in from the convection furnace (model K, 750/2S, internal capacity 55 liters) of Heraeus, DE of gained catalyst precarsor.For this reason, following program is used:

-in 72 minutes, be heated to 130 DEG C, keep 72 minutes

-in 36 minutes, be heated to 190 DEG C, keep 72 minutes

-in 36 minutes, be heated to 220 DEG C, keep 72 minutes

-in 36 minutes, be heated to 265 DEG C, keep 72 minutes

-in 93 minutes, be heated to 380 DEG C, keep 187 minutes

-in 93 minutes, be heated to 430 DEG C, keep 187 minutes

-in 93 minutes, be heated to 490 DEG C, keep 467 minutes.

After calcining, obtain the stoichiometry Mo with calculating ₁₂co ₇fe ₃bi _0.6k _0.08cr _0.5o _xcatalyst.

The ring of calcining is ground into powder.For this reason, ultracentrifugation mill (from Retsch ZM200) is used.This equipment has horizontal rotary flap, and the outer rim of swivel plate is vertically upward provided with the impact components of given number.Impact components all exists with identical interval to each other.At peritrochanteric, annular screen is installed.Rotor and sieve are arranged in comminuting space shell, and this shell seals on all sides.Only on the central authorities of rotor, there is opening.Rotor is set to rapid circular movement, and from material to be comminuted being introduced the middle part of rotor above.Material to be comminuted is pulverized by impact components and is passed annular screen.The final fineness of comminution of material is determined by the fracture behaviour of the rotating speed of the type of rotor, rotor, annular screen and material to be comminuted.

24 tooth rotors and the annular screen with 120 μm of mesh are installed.Change the rotating speed of rotor and obtain active compound A, B and the C shown in table 1.

Table 1

	Active compound A	Active compound B	Active compound C
					250.01	250.02	100.03g
The mesh of sieve	120μm	120μm	120μm
				The number of rotor tooth	24	24	24
Rotating speed	9000	11000	18000
				The introducing time, minute *	1 point 25 seconds	1 point 25 seconds	1 point 40 seconds
Gained weight	243.63g	243.18g	92.56g
				D under 0.2 bar 50	12.66	10.67	5.83

* within 30 seconds of+grinding machine, run further, manually introduce

Domain size distribution and the particle diameter d obtained by these ₅₀pass through determination of laser light scattering.Herein, each fine-powder is introduced the dry disperser of Sympatec RODOS (Sympatec GmbH by dispersion chute, System-Partikel-Technik, Clausthal-Zellerfeld, DE), in, disperse by compressed air is dry and is blown in measuring cell as free stream there.Then, in measuring cell, use Malvern Mastersizer S laser light scattering spectrometer (Malvern Instruments, Worcestershire, Britain) mensuration based on the domain size distribution of volume according to ISO13320.During measurement, the decentralization of dry powder measures by the compressed-air actuated applying dispersive pressure being used as carrier gas.Gross pressure is 1.2 bar.

The integrogram of the size distribution that Fig. 1 display represents with volume %.

The differential map of the size distribution that Fig. 2 display represents with particle %.

The carrier (steatite ring) two batches with size 7 × 3 × 4mm (external diameter × highly × internal diameter) applies with 20 % by weight active compound A and B respectively, to obtain catalyst 1 and 2.In addition, the carrier (steatite ring) two batches with size 5 × 3 × 2mm (external diameter × highly × internal diameter) applies with 10 % by weight active compound B and C respectively, to obtain catalyst 3 and 4.

For this reason, carrier is put in coating cylinder (2 liters of internal capacities, drum central axis and horizontal inclination angle=30 °).Cylinder is set to rotate (25rpm).Liquid adhesive (glycerine: the 10:1 mixture of water) is sprayed on carrier through about 30 minutes by the atomizer operated by compressed air (spray air: 500 standards l/h).The mode that the carrier carried in cylinder is wetting in the first half of the section rolled downwards is installed to make atomizer cone by nozzle.Introduced in cylinder by fine-powdered active compound by powder screw rod, wherein the interpolation point of powder is in downward rolling section, but below atomizer cone.Active compound is metered into obtain powder equally distributed mode from the teeth outwards.After coating completes, by the gained coated catalysts in drying box at 300 DEG C dry 3 hours comprising active compound and carrier.

The stability of coated catalysts can be characterized by wearing and tearing in drop test.Herein, about 50g catalyst 1-4 was introduced in vertical 350cm long-tube reactor from above through 30 second time.Take out caltalyst and lost material, be separated from each other and weigh.By the quality of the quality of lost material divided by the active compound applied.

Table 2 shows the abrasion activity composition percentage of three kinds of active compounds A, B and C on catalyst 1-4, based on the quality of the active compound put on carrier.

Table 2

Catalyst	1	2	3	4
					Active compound	A	B	C	B
The d of PSD 50	12.66μm	10.67μm	5.83μm	10.67μm
					Wearing and tearing	11.3％	10.3％	21.3％	9.2％

For being greater than 6 μm and being less than the d of 13 μm ₅₀, wearing and tearing are minimum.

Claims (13)

1. coated catalysts, it comprises:

(a) carrier,

B () comprises the shell of the catalytic activity poly-metal deoxide containing molybdenum and other metal of at least one, its mesochite is by the d with 6-13 μm ₅₀poly-metal deoxide particle make,

And obtain by following steps:

I () preparation comprises the poly-metal deoxide precursor composition of molybdenum and other metal of at least one,

(ii) formed body is prepared by poly-metal deoxide precursor composition,

(iii) the formed body calcining of poly-metal deoxide precursor composition will be comprised to produce multimetal oxide compositions,

(iv) formed body comprising multimetal oxide compositions is pulverized to form the d with 6-13 μm ₅₀poly-metal deoxide particle,

V carrier is used poly-metal deoxide particle coating by (),

(vi) by the support heat-tr eatment of coating.

2. coated catalysts according to claim 1, wherein carrier (a) has hollow cylinder shape, and its internal diameter is 0.2-0.8 times of external diameter, and length is 0.5-2.5 times of external diameter.

3., according to the coated catalysts of claim 1 or 2, its mesochite (b) has the layer thickness D of 50-600 μm.

4. coated catalysts as claimed in one of claims 1-3, wherein multimetal oxide compositions does not comprise any pore-forming agent.

5. coated catalysts as claimed in one of claims 1-4, the wherein said catalytic activity poly-metal deoxide comprising molybdenum and other metal of at least one has general formula (I):

Mo ₁₂Bi _aFe _bCo _cNi _dCr _eX ¹ _fX ² _gO _x(I)，

Wherein variable has following implication:

X ¹=W, Sn, Mn, La, Ce, Ge, Ti, Zr, Hf, Nb, P, Si, Sb, Al, Cd and/or Mg;

X ²=Li, Na, K, Cs and/or Rb;

A=0.1-7, preferred 0.3-1.5;

B=0-5, preferred 2-4;

C=0-10, preferred 3-10;

d＝0-10；

E=0-5, preferred 0.1-2;

F=0-24, preferred 0.1-2;

G=0-2, preferred 0.01-1; And

The number that the chemical valence of the element during x=serves as reasons (I) beyond oxygen and abundance determine.

6. prepare the method for coated catalysts as claimed in one of claims 1-5, described catalyst comprises:

(a) carrier,

B () comprises the shell of the catalytic activity poly-metal deoxide containing molybdenum and other metal of at least one, its mesochite is by the d with 6-13 μm ₅₀poly-metal deoxide particle make,

Described method comprises step:

I () preparation comprises the poly-metal deoxide precursor composition of molybdenum and other metal of at least one,

(ii) formed body is prepared by poly-metal deoxide precursor composition,

(iii) the formed body calcining of poly-metal deoxide precursor composition will be comprised to produce multimetal oxide compositions,

(iv) formed body comprising multimetal oxide compositions is pulverized to form the d with 6-13 μm ₅₀poly-metal deoxide particle,

V carrier is used poly-metal deoxide particle coating by (),

(vi) by the support heat-tr eatment of coating.

7. n-butene oxidative dehydrogenation is being become the purposes in butadiene by coated catalysts as claimed in one of claims 1-6.

8. n-butene oxidative dehydrogenation is become the method for butadiene, wherein the starting gas mixture comprising n-butene mixed with oxygen-containing gas and contact at the temperature of 220-490 DEG C in fixed bed reactors with the coated catalysts as claimed in one of claims 1-5 arranged with stationary catalyst bed.

9. method according to claim 8, wherein fixed bed reactors are fixed-bed tube reactor or fixed bed shell-tube type reactor.

10. the method for according to Claim 8 or 9, the starting gas mixture wherein comprising n-butene is obtained by the Non-oxidative dehydrogenation of normal butane.

The method of 11. according to Claim 8 or 9, wherein comprises the starting gas mixture of n-butene by the C from naphtha cracker ₄cut obtains.

The method of 12. according to Claim 8 or 9, the starting gas mixture wherein comprising n-butene is obtained by the dimerization of ethene.

The method of 13. according to Claim 8 or 9, the starting gas mixture wherein comprising n-butene is obtained by fluid catalytic cracking (FCC).